A macroscopic (or macro) lens for a camera is usually a converging lens of normal focal length built into a lens barrel that can be adjusted to provide the additional lens-to-film distance needed when focusing at very close range. Suppose that a macro lens (f = 53.0 mm) has a maximum lens-to-film distance of 271 mm. How close can the object be located in front of the lens?
The relationship between the distance of an object from a lens, the distance of an image from a lens, and the focal length is given simply by:
1/d_o + 1/d_i = 1/f
Where d_o is the object distance, d_i is the image distance, and f is the focal length.
In this problem, we ...
This solution is 226 words and provides an equation for focal length, and uses simple inputting of knowns to find the distance.